Unit I ETS Flashcards
What is the final electron acceptor in ETS?
oxygen
What are the final products of aerobic metabolism?
CO2, H2O, and ATP
What is oxidative phosphorylation?
Electron transport system coupled with the synthesis of ATP
Location of ETS?
inner mitochondrial membrane
How many complexes are in the ETS?
5
Which of the complexes catalyzes ATP synthesis?
The last one, ATP synthase
What is the name(s) of complex one?
NADH dehydrogenase (NADH-CoQ reductase)
Which molecule in complex one is bound and accepts electrons from NADH?
FMN
What does FMN of complex 1 become when it accepts electrons from NADH?
FMNH2
What does FMNH2 of NADH dehydrogenase transfer electrons to?
ubiquinone (CoQ)
Is complex one a proton pump?
yes
What is the name(s) for complex 2?
succinate dehydrogenase
Once oxidized, what does succinate give its electrons to?
FAD, making FADH2
what does FADH2 from succinate dehydrogenase give its electrons to?
an FeS protein and then to ubiquinone (CoQ)
Is complex 2 a proton pump?
no
What is another name for ubiquinone?
Coenzyne Q (CoQ)
What molecules does CoQ accept electrons from?
FMNH2 and FADH2
What brings FADH2 to CoQ?
succinate dehydrogenase, glycerol phosphate dehydrogenase, and Acyl CoA dehydrogenase
When electrons leak out of ETS what is created?
superoxide radicals
At what step of ETS can superoxide radicals be created?
the CoQ step
What are the cytochrome proteins of ETS?
complex 3, cytochrome C, and complex 4
What makes a cytochrome a cytochrome?
containing a heme group
Where are electrons pumped out of the inner mitochondrial matrix?
complex 3 and 4, and cytochrome C
What defines a heme group?
a porphyrin ring with iron
What is another name for complex 3?
Cytochrome reductase or cytochrome bc1 complex
Does cytochrome bc1 complex have a proton pump?
yes
Where does the electron from complex 3 get moved to?
cytochrome c
Where does Cytochrome c sends its electron?
to cytochrome oxidase
what is another name for complex 4?
cytochrome oxidase, cytochrome c oxidase, or cytochrome a + a3
What allows cytochrome c to not need a proton pump?
its location in the intermembrane space
Doess cytochrome c oxidase contain a proton pump?
yes
Instead of a porphyrin ring, what does complex 4 contain?
a bimetalllic center containing copper
What happens to oxygen between the two copper ions in Cytochrome oxidase?
it is held until completely reduced to water
How many electrons are needed reduce an O2 to make 2 molecules of H2O in ETS?
4 electrons and 1 O2
In what complex of ETS is H20 formed?
complex 4
What happens with the accumulated protons in ETS?
their energy is used to make ATP
What else can complex V be called?
ATP synthase or ATPase
How many ATP are formed from ATPase?
about 3
What is oligomycin?
an antibiotic (or uncoupler)
What is oligomycin used for?
it closes the proton channel and prevents ATP synthesis
What is the location of uncoupling proteins (UCPs)?
inner mitochondrial membrane
Describe the function of UCPs
it forces channels to form allowing protons to enter the matrix, cutting off electrons from complex V, thus stopping ATP synthesis
In UCPs how is energy released?
it’s released as heat through non-shivering thermogensis
List some synthetic uncouplers
2,4-dinitrophenol and aspirin
For a given redox pair what form will likely lose its electrons with a negative standard reduction potential?
the reduced form of the redox pair
For a given redox pair what form will likely accept electrons with a positive standard reduction potential?
the oxidized form of the redox pair
In redox pairs, how do electrons like to flow?
from a more negative standard reduction potential to a more positive standard reduction potential
From NADH, where do electrons like to flow?
to oxygen
What unit of measurement is assigned to standard reduction potential?
volts
What is needed for NADH to pass through the inner mitochondrial membrane?
a shuttle system
List then two shuttle systems used in ETS
malate aspartate, and glycerophosphate shuttle
In the malate aspartate shuttle, describe how NADH gets into the inner mitochondrial membrane?
NADH is coupled with oxaloacetate to make malate. Malate can freely cross the inner mitochondrial membrane where it can again become oxaloacetate and donate a proton to NAD to become NADH where it is used in ETS
What converts oxaloacetate to malate?
malate dehydrogenase
Once NADH is in the inner mitochondrial membrane as malate what happens?
malate is converted back to oxaloacetate
What does the conversion of malate to oxaloacetate in the inner mitochondrial membrane do?
it gives a proton back to NAD to make NADH and is used in ETS
To get oxaloacetate out of the inner mitochondrial membrane what must happen?
it is converted to alpha ketoglutarate and shuttled out.
What converts oxaloacetate to alpha-ketoglutarate in the inner mitochondrial membrane?
aminotransferase
In the malate aspartate shuttle system, what converts oxaloacetate to glutamate?
aminotransferase
Once oxaloacetate is converted to glutamate in the malate aspartate shuttle system, what happens to glutamate?
glutamate can freely cross into the inner mitochondrial membrane
What is used to get glutamate out of the inner mitochondrial membrane?
aminotransferase
To get glutamate out of the inner mitochondrial membrane, in the malate aspartate shuttle, what is it converted to?
aspartate
What enzyme converts Glutamate to aspartate in the malate aspartate shuttle?
aminotransferase
In the glycerophosphate shuttle system, the reaction of Glycerol-3-Phosphate to DHAP is catalyzed by what enzyme?
glycerophosphate dehydrogenase
What coenzyme couples with glycerophosphate dehydrogenase to donate electrons to ETS?
FAD
What enzyme is used to convert DHAP to glycerol-3-phosphate?
glycerophosphate dehydrogenase?
